I may sound like I am asking a silly question but does this work on pre-orders. I know quidco don't do it on pre-orders.
Like a lot of cashback sites, it's down to GAME's discretion. If they want to be awkward they can, but you can always try to appeal it, but it can be a lengthy process.
My advice with any kind of cashback site is, if you can afford the item, and want the item, do it, and just consider the cashback a bonus rather than a guarantee.